The specified network name is no longer available

Solution 1:

It disappeared for my when I disabled "network discovery" on Win7. I noted regular network disconnections of Win7 when it says "connected" or "identifying" repeatedly.

Here's a link (via the Internet Wayback Machine) to Microsoft instructions about how to turn network discovery on and off in Win7.

Plus, just in case that link gets broken, here's a screenshot of what it said on 2012-Sep-08:

Solution 2:

This often indicates a hardware problem with the disk(s) and/or disk controllers (I get this problem with faulty RAID controllers frequently). Check your server's event logs to see if you have any messages to that extent and run some hardware diagnostics on your server.

In response to your comment:
There are usually diagnostics that you can run in your computer's setup (BIOS), check your manual or look on Dell's site for instructions for those. Dell also has a list of tools that you can use to perform diagnostics from within Windows.